THIS GUT-WRENCHING FIRSTHAND ACCOUNT OF THE WAR IS A CLASSIC IN THE ANNALS OF VIETNAM LITERATURE. Guns up!" was the battle cry that sent machine gunners racing forward with their M60s to mow down the enemy, hoping that this wasn't the day they would meet their deaths. Marine Johnnie Clark heard that the life expectancy of a machine gunner in Vietnam was seven to ten seconds after a firefight began. Johnnie was only eighteen when he got there, at the height of the bloody Tet Offensive at Hue, and he quickly realized the grim statistic held a chilling truth.